1. Field of the Invention
This invention relates to mounted loudspeaker systems, and in particular to a mechanism compensating for dimensional variations associated with a pivoting or rotating woofer.
2. Description of Related Art
In-wall and in-ceiling mounted loudspeakers are a popular method for installing sound reproduction systems into residential and commercial spaces. They require no floor or wall space and their visual footprints are relatively innocuous. However, as a producer of accurately transmitted acoustical information, when compared to its floor or wall mounted counterparts, significant challenges must be overcome to minimize the effects of being mounted in a ceiling structure. Rarely does the installer have the luxury of installing these systems in the best locations for acoustical performance. This is typically due to aesthetic reasons and/or unmodifiable features of architecture. The principal acoustical difficulties presented by ceiling mounted loudspeakers are that the transducers are mounted inside a recessed cavity, and that listening areas are typically substantially off-axis to the transducer's default and ideal direction of propagation. To minimize artifacts caused by these difficulties, it is desirable to be able to rotate or angle the transducers toward the preferred listening area.
For a low/mid frequency transducer, this may be accomplished through use of a ball and socket system consisting of three fundamental components: a front socket that is typically integrated into a primary mounting frame structure; a back socket that is rigidly coupled to the front socket and integrated into a retaining ring structure; and a ball like structure that is either integrated into or carries the woofer assembly. Such a ball and socket system allows a limited degree of rotation or pivoting of the woofer relative to the front/back socket assembly.
A number of limitations and variables are imposed by available and cost viable manufacturing processes. These variables result in large differences in stiction (the force required to cause one body in contact with another to begin to move), and subsequently, the smoothness of movement of the woofer after its stiction is overcome. To the user/installer these variables present as either too loose or too tight, with few being judged “just right”. In order to function properly the socket moldings must be perfectly joined, aligned and spherical with adequate stability to maintain their shape. The ball also must be perfectly spherical and stable. Mating surfaces must be hard and smooth enough to allow for minimum stiction and for subsequent predictable motion. The fit between parts must both permit movement and be tight enough to hold the woofer assembly in the desired orientation regardless of any effects caused by vibration of the woofer or environmental factors such as temperature/humidity variations. These environmental and manufacturing factors both individually and collectively act to work against ideal fit and operation. However, even when the components are perfect and properly assembled, there are conditions that can potentially thwart consistent functionality, and reliance on “perfect parts” is folly as the tolerances required fall outside the capability of available manufacturing processes.